Research And Realization Of Reversible Speed Control System Based On Energy Manager

With the rapid developments of power electronics and digital control technology, PWM converter, which is constituted by full-controlled switching device, has been widely used in power electronic devices. Due to the features of adjustable power factor, less harmonic component of AC side current and double direction energy flowing, PWM converter is able to realize the forward and backward operations of speed control system, which satisfies the national policy trends of energy saving and environmental protection. Using PWM converter as a basic unit, back-to-back converter can be assembled and applied to speed control system, which is the hotspot and research trends of high performance motor drive system. In this thesis, based on the topology of back-to-back converter, reversible speed control system has been researched particularly, and the control strategy of reversible speed control system has been proposed. Focusing on the characteristic of energy flowing during the system transient process, a energy management strategy has been established.Firstly, considering the different operation model of reversible speed control system, the topology and mathematical function of reversible speed control system are analyzed. After that the explicit control requirements of bidirectional operations are indicated. Secondly, basing on the mathematical models of the system, vector control strategy, SVPWM modulation technique and double closed-loop are utilized in order to build the control strategies of forward operation and backward operation. For the transient process between forward and backward operating which is the difficulty during the control process,, the energy flowing equations are established. According to model reference adaptive system theory, an rotational inertia identification is achieved. And using the results of rotational inertia identification, the operation status of the speed control system are coordinated dynamically, which makes the reversible speed control system operating continuously and independently in transient process. The series control strategies have been verified in Matlab. A large number of simulation results have shown that remarkable speed control performance could be reached by using these strategies.On the basis of theoretical analysis and simulation results, hardware and software designs have been accomplished in this thesis. The design and realization processes of hardware and control software of reversible speed control system based on back-to-back converter have been explained in detail.Finally, based on a 3.5kW permanent magnet synchronous motor experiment platform, the reversible speed control system which is proposed in this thesis has been tested. Focusing on the main phenomena and results during the experiment, the system performances in forward operation, backward operation and transient process have been analyzed. Experiment results have verified the feasibility and correctness of the hardware and control strategies designs of the reversible speed control system, which are the technology and theoretical foundations for subsequent research works.